Oil sight glass



FIG. 1 is a front perspective view of an oil sight glass showing the new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a sectional view thereof, taken along the line shown in FIG. 3 . 

CLAIM The ornamental design for an oil sight glass, as shown and described. 